1. Field of the Invention
The present invention relates to high purity intravenously injectable gamma globulin (IgG) preparations and a process for preparing the same. More particularly, the invention relates to a product and method of making unmodified, unaltered, undenatured or native gamma globulin molecules of high purity for intravenous administration.
The invention also relates to high purity intravenous hyperimmune globulin preparations having increased antibody titers to sixteen serospecific strains of Pseudomonas aeruginosa and the method of making such preparations.
It has been known for some time that certain patients with humoral immunodeficiencies are susceptible to acute and chronic infections which sometimes assume life-endangering dimensions. These patients are not able to produce the required levels of antibodies and the same must be supplied to them for the prevention and treatment of such infections.
The immune globulin fraction of pooled human plasma contains antibodies to many viruses and bacteria and thus is effective in the management of various diseases including those associated with Staphylococci, Streptococci, Coli, Pseudomonas, Herpes zoster and pyocyaneus septicemias.
Patients with normal levels of antibodies also require additional defense in overcoming serious infections such as caused by Pseudomonas aeruginosa.
Immunogenic pseudomonas vaccines and globulins having raised titers of protective antibody and increased phagocytic activity were found effective in the treatment of infections caused by Ps. aeruginosa.
Human immune globulins were first isolated on a large scale during the 1940's by F. J. Cohn. It was also observed that the aggregate formed during the fractionation procedure results in anticomplement activity and that clinical application causes adverse reactivity in the patient.
2. Description of the Prior Art
It has been known to prepare immune globulin containing antibodies by fractioning human blood plasma according to the so-called Cohn-method. It has also been known to further purify immune globulin for administration either intramuscularly or intravenously. While producing some of the desired effects, both kinds of administration have some disadvantages, which at times, may be serious or even life-threatening.
Intramuscular injections of immune globulin have proven effective in raising the level of circulating immune globulin and in decreasing the length, frequency and severity of infections in some patients. There are patients, however, who cannot achieve adequate immune globulin levels and protection from infection with intramuscular administration of immune globulin. Such patients when treated via plasma therapy experience improvement which indicates that intravenous administration may have advantages over the intramuscular route. Other disadvantages of intramuscular administration of immune globulin include the delayed onset of reaction resulting from the slow diffusion of the substance into the circulation, and inconsistent absorption and local degradation in the muscle where the injection is administered.
With intravenously administered immune globulin adequate levels of circulating antibody could be reached immediately and controlled by the rate of infusion. The intravenous route of administration also overcomes the effects of inconsistent absorption and local degradation in the muscle. Also, patients with small muscle mass or bleeding tendency tolerate an intravenous injection better than an intramuscular injection.
While intravenous administration is the preferred route of administration, the product so administered is not without some serious drawbacks. It is known that intravenously administered immune globulin may cause unpleasant side effects such as flushing, wheezing back and muscle pain, anxiety and hypotension. It has been observed that these side effects may be due to the activation of complement, secondary to the formation of immune complexes, aggregates of immune globulin and denatured globulin formed during the storage thereof.
The prior art has made great efforts to prepare immune globulin which has lesser anticomplement activity, mainly by decomposing or removing the aggregated or denatured globulin. Such efforts included: enzymatical hydrolysis using pepsin, plasmin, papain, or bacterial proteases; chemical tratment by an acid, propiolactone or the like; conversion of the immunoglobulin into a chemical derivative such as by amidation, alkylation or S-sulfonation; and fractional precipitation of the immunoglobulin using polyethylene glycol or the like.
While these methods seemed to decrease the presence of aggregated or denatured globulin in the final products and consequently lowered the anticomplement activity, they were not without other shortcomings, such as low activity of the antibody, shortened half-life time of the immunoglobulin in the blood, and the presence of some denatured impurities which is believed to cause a decrease in efficacy of the immunoglobulin.
To overcome the above-mentioned disadvantages, the prior art has further proposed various preparative methods for intravenous immunoglobulin. Illustrative of these are the methods disclosed in the following patents:
U.S. Pat. No. 4,256,631 discloses a process for the preparation of immunoglobulin for intravenous administration comprising the purification of immunoglobulin by a combination of a fractional precipitation method in which one or more divalent or trivalent metal salts are added to an aqueous solution of the immunoglobulin and the supernatant is processed by affinity chromatography using as an adsorbant a complex of human IgG and a polyhydroxy polymeric compound. The resultant immunoglobulin is said to be extremely pure.
U.S. Pat No. 4,305,870 pertains to a method for making intravenous plasma derivatives which includes the steps of mixing bentonite and an aqueous solution of plasma derivatives containing exogenous activity, the bentonite and the mixing time being sufficient to adsorb exogenous activity, and isolating the aqueous phase from the bentonite. Optionally, for the removal of residual exogenous activity, the bentonite-treated aqueous phase is further purified by ion-exchange chromatography. The so-obtained product is said to have an acceptable low content of externally deleterious or exogenous activity.
While the above-noted attempts by the prior art greatly enhanced the success of treatment of various infectious diseases by producing satisfactory immunoglobulin for such treatment, none to our knowledge has produced a natural, unmodified, unaltered and undenatured product which desirably should have the following characteristics: it should contain substantially pure Immunoglobulin G (IgG) so that it is substantially free of naturally occurring IgA and IgM antibodies; it should contain all subclasses of IgG, namely IgG.sub.1, IgG.sub.2, IgG.sub.3, and IgG.sub.4 in substantially the ratio as they occur in blood plasma; spontaneous complement activation should be very low or absent; it should be free of polymeric IgG; and it should have a very low level of trace constituents, such as enzymes which tend to degrade and destabilize IgG during storage.
The underlying reason for the production of such a natural product will be easily ascertained by those skilled in the art from the following brief explanation.
The native IgG molecule is known to have two types of biological activities, namely, the immune-specific activity and the non-immune-specific or "effector" activity. The immune-specific activity is characterized by binding properties for specific antigens whereby the IgG molecule acts as an antibody. The non-immune-specific or "effector" activity includes binding and activation of complement, opsonic activity, and the binding to specific cellular receptors for the Fc portion of the molecule. Any change in the native IgG molecule which alters, reduces or eliminates either of these two types of activities is referred to as denaturation whether said denaturation is the result of intentional or unintentional chemical or enzymatic modification. Commercial preparations of intramuscular IgG, which are processed withouth chemical modifications, contain aggregated forms of IgG that cause high levels of spontaneously fixed and activated complement and are examples of unintentional denaturation. Examples of intentionally denatured IgG molecules include IgG preparations that are modified with the use of chemicals and/or enzymes in an attempt to improve the safety of intravenous administration. Such intentional denaturation diminishes or even completely eliminates the effector functions of IgG and reduces the total beneficial biological potency of the IgG.
In addition to the desired characteristics described above, a Pseudomonas immune globulin preparation must possess preformed, specific anti-Pseudomonas antibodies. Host defense for Pseudomonas depends upon the presence of adequate numbers of functional phagocyte cells plus serum opsonic activity. Optimal phagocytosis of Pseudomonas occurs in the presence of type-specific Pseudomonas antibody. At least seventeen separate strains of Ps. aeruginosa have been identified by the World Health Organization, many of which show unusual resistance to treatment with antimicrobial drugs. Each strain is characterized by localized infections that may overwhelm the host tissue. Endotoxin, toxin A, elastase and protease are released to further weaken the host's defensive mechanism. Clinical cases in which normal immune defenses are compromised, such as burn, cancer and cystic fibrosis cases are particularly susceptible to infection by Ps. aeruginosa. A fast acting intravenous injection of hyperimmune, polyvalent gamma globulin to enhance specific antibody activity can be of life-saving to these patients.
Anti-Pseudomonas immune globulin, immune whole blood and immune plasma are known in the prior art. Notwithstanding their beneficial properties, their drawbacks include having limited antibody titers, protection against only some of the recognized strains of Ps. aeruginosa, and the lack of high purity.
It is, accordingly, an object of the present invention to provide a native gamma globulin preparation suitable for intravenous injection.
It is another object of the present invention to eliminate undesired denatured properties of IgG not by the alteration of effector functions but by the selective elimination of molecular forms of IgG which are denatured and at the same time eliminate impurities in the form of non-IgG proteins.
It is still another object of the present invention to provide a gamma globulin preparation suitable for intravenous administration, in which anticomplement activity is less than about 0.1 C'50 units/mg.
It is a further object of the present invention to provide a gamma globulin preparation containing at least 99.0% pure immune gamma globulin which is essentially free of IgA and IgM.
It is also an object of the present invention to provide a gamma globulin preparation containing all subclasses of IgG, namely IgG.sub.1, IgG.sub.2, IgG.sub.3, and IgG.sub.4, in substantially the ratio as occurring in normal blood plasma.
A further object of the present invention is to provide an intravenous, hyperimmune globulin preparation with increased antibody titers to sixteen serospecific strains of Pseudomonas aeruginosa.
A still further object of the present invention is to provide an intravenous, hyperimmune globulin preparation with increased antibody titers to sixteen serospecific strains of Pseudomonas aeruginosa in which anticompliment activity is less than about 0.1 C'50 units/mg.
Another object of the present invention is to provide an intravenous, hyperimmune globulin preparation which is essentially free of IgA and IgM.
It is still another object of the present invention to provide a simple economical process for commercial preparation of immune gamma globulin.
These and other objects and advantages of the present invention will be readily apparent to those skilled in the art from the description of the invention that follows.